Synthesis Of Star-shaped Conjugated Oligomers And Their Optoelectronic Response Performance

As a new kind of functional organic materials, conjugated oligomers are getting moreand more attention because of their excellent optical and electrical properties. With the aim ofdeveloping new properties and getting wider application of conjugated oligomers. Newstar-shaped conjugated oligomers,1,3,5-Tri(2′-thienyl)benzene (3TB),1,3,5-Tri[5′,2′′-(3′′,4′′-ethylenedioxythineyl)-2′-thienyl)]-4-(3′,4′-ethylenedioxythineyl)benzene (3TB-4EDOT),2,4,6-Tri(2′-thienyl)-1,3,5-triazine(3TT) were designed and synthesized. These star-shapedconjugated oligomers were charactered by MS,1H-NMR,13C-NMR, IR. Their thermalperformance were tested by DSC. Their optical and electrical properties were stutied. Theirpotential application in electrochromic device and solar cell were investigated.The photophysical and electrochemical properties of these star-shaped conjugatedoligomers were measured by UV-Vis absorption spectra, fluorescence spectra and cyclicvoltammetry, based on the relationship between molecular structure and optical, electricalproperties which were studied.Two kinds of electrochromic devices were fabricated, which are based on electrochromicactive layer/electrolyte solution(device1) and electrochromic active layer/conductinggel(device2). Divice1is ITO(indium tin oxide)/electrochromic active layer/electrolytesolution/Pt. In device2, the ITO-coated glass was serviced as the electrode, electrolyte wasconducting gel.3TB,3TB-4EDOT,3TT were served as the electrochromic active layer, andthe electrochromic mechanisms were also be discussed. It was found that3TB and3TTrevealed reversible, obvious colour change by electrochemical doping and dedoping. Thereversible color changes of the electrochemical doped films of3TB and3TT were separatelyfrom blue to colorless and orange-yellow to colorless. Whereas3TB-4EDOT wereelectropolymerized firstly, and then switched the colors when the applied potential changed.The reversible color changes of the electrochemical doped films of poly(3TB-4EDOT) was from deep blue to blue-gray，then to orange-red.The photovoltaic properties of3TB,3TB-4EDOT and3TT were studied. The organicphotovoltaic devices were fabricated as follows: ITO/conjugated oligomers/PTCDA/Al.The power conversion efficiency of photovoltaic cells based on3TB,3TB-4EDOT and3TTwere separately0.24%、1.01%and0.35%.